Colorado radiator

Submitted: Monday, Jul 15, 2019 at 17:50
ThreadID: 138727 Views:1772 Replies:11 FollowUps:27
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Hi all.

I have an RC 2011 4 speed auto diesel.

When towing our van it gets a bit hot up long hills.

Has anybody fitted a bigger radiator to their ute.

Regards....... Peter
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Reply By: Hewy54 - Monday, Jul 15, 2019 at 18:14

Monday, Jul 15, 2019 at 18:14
Could try fitting a trans cooler.
I have a BT50 and had the same problem. Temperature was not over the top, but enough to cause me a bit of a concern.
Fitted a trans cooler and not had a problem since.
AnswerID: 626749

Follow Up By: Bravo Man - Monday, Jul 15, 2019 at 18:45

Monday, Jul 15, 2019 at 18:45
Sorry I didn't explain properly.

Its the engine that gets hot.

I have already fitted a trans cooler.

Thanks for your reply
FollowupID: 900669

Reply By: RMD - Monday, Jul 15, 2019 at 19:01

Monday, Jul 15, 2019 at 19:01
Bravo Man
When towing, especially when towing and uphill, quite often the torque converter is in slip mode, ie acting as a torque converter does. Because there is a reasonable or high degree of internal slip/hydraulic turbulence, it is converting quite a bit of engine power into increased level of heat in the auto. Many times the fluid exiting the torque converter is well above engine water temperature.,ie, 90C engine and 130 C or more, as it leaves the torque converter. That temp is NOT the temp the auto is running at because it is cooled to some degree by the heat exchanger in the radiator bottom and that is what is read by the auto’s temp sensor for the ECU to act on. You DO NOT need a bigger radiator as it will not cool the auto any faster, because the flow rate and size of the heat exchanger in rad bottom. As mentioned in above post, the way to control the heat input to the radiator water from the auto’s action, is to fit a transmission cooler in the EXIT LINE from the auto. That ensures the maximum heat differential and dissipation of heat to the ambient temp BEFORE the fluid enters the radiator heat exchanger and therefore lessens the heat load the radiator is trying to get rid of. That then means the engine now actually has a RESERVE of cooling, as designed and keeps the engine at a more constant temp and below a thermal runaway threshold. Many people are blissfully unaware how close they really are to thermal runaway if both auto and engine. If either device stops because of overheat, your travel is finished. A tail wind when all is too hot may well may see you stopped.
It is all a balance of thermal dynamics.
PS, some auto trans coolers can be small but have an electric fan which can be switched on to blast ambient air through the suitable cooler and keep things under control. Fan never used in cold/normal towing.
AnswerID: 626750

Follow Up By: Bravo Man - Monday, Jul 15, 2019 at 19:08

Monday, Jul 15, 2019 at 19:08
Trans cooler has already been fitted, no problems with trans temp.

Temp gauge for the engine creeps up.

FollowupID: 900671

Follow Up By: RMD - Monday, Jul 15, 2019 at 20:00

Monday, Jul 15, 2019 at 20:00
If trans temp is ok then it has to be thermo fan clutch in water pump pulley, poorly maintained radiator, ie blocked cores, or the thermostat is tired and is not opening sufficiently to allow cooling flow through engine to be normal. Fan clutch and thermostat checks/ replacement first of all.
I have seen some similar vehicles with a myriad of lights and towing huge vans quite ok.
FollowupID: 900677

Reply By: Member - Scrubby (VIC) - Monday, Jul 15, 2019 at 19:13

Monday, Jul 15, 2019 at 19:13
I had a similar problem until I removed the Warn Winch Solenoid Box and replaced it with an electronic one fitted inside the engine bay. I also got rid of the 7" driving lights and fitted 4" ones , now got heaps more air through the radiator and engine runs cooler.

I don`t know where i`m going but i`m enjoying the journey.

My Profile  My Blog  My Position  Send Message

AnswerID: 626751

Follow Up By: Bravo Man - Monday, Jul 15, 2019 at 19:16

Monday, Jul 15, 2019 at 19:16
I do have driving lights and was wondering about that.

Might have to remove them.

FollowupID: 900672

Reply By: Shaker - Monday, Jul 15, 2019 at 19:58

Monday, Jul 15, 2019 at 19:58
You say it's a 2011 model,
How long have you been towing with it?
Has the overheating only just started?
How long have the driving lights been fitted?
Have you had the radiator checked/cleaned?
Have you checked the fan viscous coupling?
Does it cool down quickly once you clear the crest of hill?
AnswerID: 626754

Follow Up By: Bravo Man - Monday, Jul 15, 2019 at 20:04

Monday, Jul 15, 2019 at 20:04
Only gets hot when towing and going up long hills
Driving lights have always been on it
Rad has not been checked but always serviced and coolant has been changed
Viscous coupling feels fine
Cools down quickly after hills
FollowupID: 900679

Follow Up By: Shaker - Monday, Jul 15, 2019 at 20:45

Monday, Jul 15, 2019 at 20:45
Sounds like a cooling system problem more than a motor issue, has it always got hot under heavy load?
FollowupID: 900686

Reply By: Ron N - Monday, Jul 15, 2019 at 21:04

Monday, Jul 15, 2019 at 21:04
Bravo Man - Have you tried replacing your thermostat? When thermostats get tired, they fail to open fully and they restrict the coolant flow.

The cooling system may be able to cope O.K. with normal loads, but when it comes to a long heavy pull up a grade, the system can no longer cope with the increased heat load carried by the coolant, exacerbated by the restricted flow rate.

Cheers, Ron.
AnswerID: 626755

Follow Up By: Bravo Man - Monday, Jul 15, 2019 at 21:12

Monday, Jul 15, 2019 at 21:12
Good point,I will look into that
FollowupID: 900689

Follow Up By: Shaker - Monday, Jul 15, 2019 at 23:36

Monday, Jul 15, 2019 at 23:36
You could replace it with a high flow thermostat.
FollowupID: 900690

Reply By: Gbc.. - Tuesday, Jul 16, 2019 at 06:43

Tuesday, Jul 16, 2019 at 06:43
First Isuzu engine? The thermostat graduations are over a much smaller area than those of a Toyota (for example) temp gauge. The same thing happens in every engine (heat up towing uphills) , your RC temp gauge just shows it more accurately. If you ever get over to the NT with a roof top tent you can drive by the temp gauge all day. 125 kph is fine, but push to 130 and watch the gauge run up. I had an auto RC for 6 years. You’ll get used to watching what your engine is actually doing, rather than having gauges that gloss over the facts. Your car is fine. If you ever tow in sand or drive through a desert with it, go to low range as early as possible - it will heat up the auto box in high range pretty quickly but lug away all day in low range no problem.
AnswerID: 626758

Reply By: Athol W1 - Tuesday, Jul 16, 2019 at 08:57

Tuesday, Jul 16, 2019 at 08:57
Have you checked that there is no rubbish build up between the Air Conditioner condenser and the radiator and also that the radiator core air flow is clean, it may require the removal of the radiator to check and/or clean this area.

If all else checks out then I would not hesitate to replace the fan clutch, as these units can appear to be working with a static test, but when the temp increases they often fall short. These units are readily available from the after market suppliers.

It is sometimes possible to add some fluid to the TSVC and improve their performance, fluid is available from Toyota dealers.

AnswerID: 626760

Reply By: RMD - Tuesday, Jul 16, 2019 at 12:14

Tuesday, Jul 16, 2019 at 12:14
You didn't say which line the auto trans cooler was inserted into. ie, the exit from the auto or the return line.

Just having one fitted can mean different things. IF your trans cooler is located in the return line to the auto, then the very hot fluid IS firstly being delivered to the radiator water and increasing the heat load delivered to the water, which is vital to keep the engine cool. Therefore, everytime you work it hard the cooling system is near maxing out and the trans cooler is only cooling a lesser amount of heat for the returned auto fluid.
Having the trans cooler in the exit line from the auto changes this fact quite a bit and may solve the problem if no other faults are present. The problem with radiator heat exchangers is, they deliver lots of heat to the immediate quantity of water about to enter the water pump and engine to keep it cool. Silly really.
Many people immediately think of a bigger radiator, which means more core rows which impede cooling airflow and all too often doesn't solve the problem.

In your case, you could fit a temp gauge to the bottom of the radiator to see the temp there, it has to show water temp cool enough to absorb the engine heat it is about to receive without exiting the top hose above a critical temp. If the bottom temp is close to the top temp then there is scarcely any cooling ability left and engine temp will soar.
AnswerID: 626762

Follow Up By: Bravo Man - Tuesday, Jul 16, 2019 at 17:43

Tuesday, Jul 16, 2019 at 17:43
The trans cooler was fitted as per instructions on the package
FollowupID: 900698

Follow Up By: RMD - Tuesday, Jul 16, 2019 at 20:23

Tuesday, Jul 16, 2019 at 20:23
Many, many, many fitting instructions and even so called auto experts fit coolers in the wrong position to be the most effective when the system begins to get too hot.. Find out which line yours is in so the effectiveness can be MAXIMIZED and not compromised. I don't know where yours is situated but feeling the lines from the auto and detecting which one is the hottest is where the cooler should be if you actually want it to work for you. If it is already in the hottest line, ie, the exit from the auto then you may have an additional problem, like the fan clutch or thermostat dodgy.
FollowupID: 900699

Follow Up By: Athol W1 - Wednesday, Jul 17, 2019 at 14:45

Wednesday, Jul 17, 2019 at 14:45
Whilst there is a lot of discussion about which line the transmission cooler should be fitted to, and even vehicle and transmission, and for that matter even the transmission coolers, manufacturers can not agree. The fact of the matter is that ANY COOLER fitted to ANY transmission line will reduce the heat load on the engine radiator.

Some argue that the additional cooler be fitted into the Hot line, so that the heat of the radiator cool tank will reinstate any overcooling of the transmission oil, therefore maintaining correct transmission operating temp. This may apply to a limited number of vehicles that will not select top gear until the transmission attains a pre-set temperature.

Others will maintain that the fitment of the additional cooler into the hot line will help to cool the cool tank of the radiator, therefore reducing the coolant from overheating.

Others maintain that the fitment into the COOL line from the radiator will help save the transmission from overheating.

So it does not matter what your argument is the simple fact is that the addition of a cooler IS assisting in the removal of heat in the entire cooling system (Engine AND transmission), as when the transmission is running cooler then there is less heat load being placed into the engine coolant by the transmission.

FollowupID: 900721

Follow Up By: RMD - Wednesday, Jul 17, 2019 at 15:14

Wednesday, Jul 17, 2019 at 15:14
Only one position for the auto cooler gets rid of the most heat before ever getting to the radiator, cooling system or returned to the auto. Can easily be measured with a temp gauge.
If over cooling becomes a problem the cooler can be partially or fully covered in cold weather IF it becomes a problem.
You said, "The fact of the matter is that ANY COOLER fitted to ANY transmission line will reduce the heat load on the engine radiator".
Hardly, as the cooler in the return line has already allowed the Maximum heat to be delivered to the bottom tank of a hard working engine and the returning fluid then remains significantly hotter as it renters the auto again and then gets another dose of heat from the torque converter to UP it's temp to a higher than desired level. Overall it will run everything hotter and closer to the maximum and leaves far less reserve cooling capacity.
FollowupID: 900722

Follow Up By: axle - Wednesday, Jul 17, 2019 at 15:19

Wednesday, Jul 17, 2019 at 15:19
Bloody good explanation Athol!!, and so as the original poster bashes his head against the wall, with all this, good old ExploreOz keeps motoring along...LOL.

Cheers Axle.
FollowupID: 900723

Follow Up By: Frank P (NSW) - Wednesday, Jul 17, 2019 at 18:16

Wednesday, Jul 17, 2019 at 18:16
Maybe it's best to remove the transmission cooler circuit completely from the engine cooling circuit. That is what most folk who have put an after market trans cooler on a PX or later Ranger or BT50 equivalent. We do that because the OEM cooler does not go through the radiator itself.

The end result is that the engine cooling system looks after itself in isolation, as does the after market trans cooling system.
FollowupID: 900727

Follow Up By: Athol W1 - Wednesday, Jul 17, 2019 at 20:41

Wednesday, Jul 17, 2019 at 20:41

I will now refer to MY experience, with 2 different Isuzu Dmax vehicles.

Firstly a 2015 model with 5 speed transmission. In this case the fitment of the cooler to the 'cold' line resulted in the fully warmed up transmission temp dropping from 95 deg when operating car only, to around 60 to 65 deg (depending on ambient temp),Engine temp being 88 to 92 under the same conditions.

Th same vehicle trans dropping from around 135 deg to 90 deg when towing my 3 tonne van up Cunninghams Gap, the engine temp also dropped from better than 120 to 95 on the same hill. (First climb in October, next climb in February)

The second vehicle being a 2017 model with 6sp transmission. This vehicle saw similar temp drop when vehicle only, and when put to the test on Cunninghams Gap (the same hill with the same van) the transmission did not get to 85, on a day when the ambient was 35 deg.

Both vehicles were driven to maintain as close to the posted speed limit, with the 6 speed capable of exceeding the posted limit.

Now you are telling me that I have things all wrong.

Frank P
Like it or not with the bT50/Ford Ranger you do not have any option but to remove the original heat exchanger if you want to fit any additional or alternative transmission cooler, as the original heat exchanger fits directly to the side of the transmission.

FollowupID: 900732

Follow Up By: Frank P (NSW) - Wednesday, Jul 17, 2019 at 20:55

Wednesday, Jul 17, 2019 at 20:55

"Like it or not with the bT50/Ford Ranger you do not have any option but to remove the original heat exchanger if you want to fit any additional or alternative transmission cooler, as the original heat exchanger fits directly to the side of the transmission."

That was exactly my poorly expressed background. The point I was trying to make is that perhaps it is better to isolate engine cooling and trans cooling from each other. It has worked very well, for my BT50.

FollowupID: 900733

Follow Up By: RMD - Thursday, Jul 18, 2019 at 10:12

Thursday, Jul 18, 2019 at 10:12
You are falsely assuming I am saying you are wrong. Never said that at all. Yours may work ok as you have mentioned,
most do but, your system has to be constantly dealing with full torque converter exit temp delivered to the radiator. Yes it is designed to handle it to a fair degree. Therefore you are still delivering maximum heat load to the radiator water , which if the cooler is in the hot line maximizes the heat dissipation BEFORE the fluid gets to the radiator system. Highest level of temp differential means more heat transfered away from the system and therefore not having any effect on that system. I think we are talking about getting rid of heat from the whole system, engine and auto.
FollowupID: 900742

Follow Up By: Athol W1 - Thursday, Jul 18, 2019 at 11:21

Thursday, Jul 18, 2019 at 11:21

You are quite obviously one of the persons who I referred to in the second and third paragraph of my post of the 17th, and I am not arguing that you are incorrect. However the other argument is also quite valid.

Any heat removed from the transmission oil will result in lower transmission sump temperature, and this lower sump temperature will result in a corresponding reduction in the convertor out temp, which results in a lower temp of the transmission oil being delivered to whatever cooling system is being employed. Therefore by reducing the temperature of the transmission return oil you are reducing the overall temperature of the oil in the transmission system which also reduces the temperature of oil coming out of the convertor which also reduces the heat load, and possibly place a negative heat load (oil cooler than the coolant), on the engine cooling system ( exactly what you are promoting with placing the cooler before the radiator, or in the hot line).

There are some vehicle and transmission manufacturers who cause an increase in the transmission oil flow through the system to ASSIST in the cooling of an overheated engine, so it is expected in these cases the transmission sump area is assisting in the dissipation of the heat load, and also that the convertor out oil temp is below that of the radiator cool tank. I am at a loss as to when, in normal operation, you would see an overheating engine that is not also accompanied by a hard working and probably overheating transmission, but I am only a Motor Mechanic and not an engineer.

I say again, unless there is a requirement for the transmission to attain a given temperature before it will select the top gear then it is purely a matter of opinion as to which line is correct, as either line will relieve or remove heat load from the entire (or combined) cooling system.

FollowupID: 900745

Reply By: swampy - Tuesday, Jul 16, 2019 at 18:11

Tuesday, Jul 16, 2019 at 18:11
Do we actually no what deg cel. the driveline is getting to??
Trans pan oil temp ?
Engine coolant ?
Engine oil ?

Ideally temps should be 90-- 98 deg cel constant
Only 105 deg cel intermittently for short periods only
AnswerID: 626771

Follow Up By: RMD - Tuesday, Jul 16, 2019 at 20:27

Tuesday, Jul 16, 2019 at 20:27
It seems not much has been investigated and the owner is unsure of many concepts and not able to appreciate the sensible feedback options offered. Once learnt the concepts then can be investigated and problems rectified.
FollowupID: 900700

Reply By: Darian - Wednesday, Jul 17, 2019 at 09:25

Wednesday, Jul 17, 2019 at 09:25
Not sure if the Scanguage has been mentioned above. Plugs in to the OBD port ...mounted on the dash (its quite small) and displays accurate data while mobile. You can choose your 4 most important parametèrs to monitor while mobile...others can be seen at the press of a button. As I understand it, this data is real, while factory gauges are near on, depending....
I use mine primarily to monitor auto trans temp while towing our van (and, as I was alerted by others, towing in manual mode reduces auto fluid heat levels to a great extent, in our Toyota's Aisin auto trans).
AnswerID: 626782

Reply By: Bravo Man - Thursday, Jul 18, 2019 at 16:43

Thursday, Jul 18, 2019 at 16:43
The original question was has any body fitted a bigger radiator to their Colorado, I was aiming this question at fellow Colorado owners. Maybe its normal for this model for the temp gauge to go up a bit under load.

I appreciate all the advice and different opinions but it has gone a bit off track.
As Axle mentioned I was starting to bang my head on the wall.

So thanks again but please this post is dead. (no more comments)

Regards Peter

AnswerID: 626803

Follow Up By: OzzieCruiser - Thursday, Jul 18, 2019 at 17:27

Thursday, Jul 18, 2019 at 17:27
Now you know what is is like to put up something on the "I am always right silly old fart forum".

Unfortunately I am not able to contribute meaningful comment on your dilemma hence I have remained quiet except for this last point.

Maybe others need to argue less and contribute more to the issue being asked.

FollowupID: 900750

Follow Up By: Frank P (NSW) - Thursday, Jul 18, 2019 at 20:57

Thursday, Jul 18, 2019 at 20:57
It's a shame that people cannot offer knowledge and experience in a DISCUSSION FORUM without being taken to task.

If responders had handcuffed themselves to the specific question the OP asked there would not be a single response in this thread.

How useful would that have been?

Bravo Man, if you wanted responses from Colorado owners perhaps a Colorado forum would have been a better bet.
FollowupID: 900753

Follow Up By: RMD - Thursday, Jul 18, 2019 at 21:32

Thursday, Jul 18, 2019 at 21:32
Anyone having an immediate thought that a bigger radiator cures problems is a flawed notion. This was pointed out and perhaps should be acknowledged. Often folk don't want to face the truth, but I agree with Frank, if no one has fitted a larger radiator then, no replies. Many possible effects/faults were covered by suggestions to diagnose or manage the situation.
Only after some suggestions, the OP then replied he had an auto cooler, some discussion was entered into. Quite normal. If the technical info given is not understood, then further questions can clarify the issue and still direct the OP to the wisest and least expensive method of rectifying his problem. That is what we try and do. Just to finally reiterate the original question leads nowhere because it is not wise. Some appreciate and act on info or have it checked for correctness and later reply what they had done solved the problem, however this is rare and many OP's don't seem to care, they got what they wanted.

YES a bigger radiator may fix the problem at considerable cost, only because it is clean, but just an OE clean one may work just as well and as designed, if blocked radiator is the fault.
FollowupID: 900754

Follow Up By: Gbc.. - Friday, Jul 19, 2019 at 08:33

Friday, Jul 19, 2019 at 08:33
Just read your manual mate, there is nothing wrong with your ute. The gauge going from 1/3 to 3/4 up the gauge and STILL NOT being in the red is perfectly NORMAL on your model. When the air con turns itself off you know you are flogging it and that will be in deep sand towing very hard. Search this forum for our posts back in 2008 when we had brand new ones and they did EXACTLY the same thing. I treated my RC fairly poorly and couldn't hurt it. Nothing you do will stop it going up and down because it is an accurate gauge which is giving you meaningful information. Be thankful. Adding a tranny cooler may help (I never did), but rest assured you aren't operating outside of any normal parameters.
FollowupID: 900765

Follow Up By: swampy - Friday, Jul 19, 2019 at 09:00

Friday, Jul 19, 2019 at 09:00
Yet no one has come up with actual operating temp in deg cel for the vehicle in question .
Normal op temp not towing on flat road
Normal op temp towing [kgs??] on flat road
Operating temp going up hill with van
All of these in similar day time temp eg under 30 deg cel

Measure temp increase

New thermostat
check fan operation
clean out internal radiator core
re measure temp increase
If operating for more than minutes above 100 cel increase radiator size
FollowupID: 900766

Follow Up By: Ron N - Friday, Jul 19, 2019 at 10:48

Friday, Jul 19, 2019 at 10:48
Bravo man, you're not alone in this Colorado/D-Max overheating issue. See the linked discussion thread, below.

It appears that the airflow through the cooling system is barely adequate at best on these Isuzu-based vehicles.
One D-Max owner had an improvement in operating temperature by removing the A/C condensor thermo fan, which apparently improves the airflow.

I have a mate with a 2005 Rodeo (manual) and we did a cleaning session on the condensor and radiator, and I noticed how "tight" the fit is, of all the cooling components. There's not a lot of spare capacity there, by way of airflow.

I noted that one poster (marknx) in the linked thread claimed that he installed a manual radiator, along with a transmission cooler with its own radiator, and this cured the overheating problem he'd had.

The theory is that the cooling tubes for the auto tranny in the automatics radiators slows down the engine coolant flow, which creates the engine heat buildup on long pulls on steady gradients.
The manual radiator doesn't have the coolant tubes for the auto, thus the engine coolant can circulate at a better rate, leading to improved heat transfer to the air.

This does make sense, it could be well worth a try, just sourcing a manual Colorado radiator in good condition from a wreck, and installing it.
You will have to modify your auto tranny cooler, of course.

D-Max overheating under load

Cheers, Ron.
FollowupID: 900770

Follow Up By: RMD - Friday, Jul 19, 2019 at 12:13

Friday, Jul 19, 2019 at 12:13
The heat exchanger in a radiator does not impede water flow, the clear space around it is greater than the hose diameter. Fitting a manual radiator and a cooler, simply means you are not bashing great quantities of heat into the water about to enter the engine for cooling purposes. Thermal dynamics at work there.

A thinner radiator core with one row of tubes can pass far greater quantities of heat to the air with the same adequate airflow. That principle is used in a trans cooler to get rid of heat.
FollowupID: 900775

Follow Up By: Frank P (NSW) - Friday, Jul 19, 2019 at 13:01

Friday, Jul 19, 2019 at 13:01
So if the OP is still following the discussion (maybe not?) he could save money by leaving the auto radiator in, blocking off the trans fluid connections and installing a stand-alone air-to-oil cooler.

As I said in an earlier post, a stand-alone tranny cooler is what we BT50 and Ranger owners are forced to do if we want a tranny cooler.

I had a similar problem to the OP's with my BT50. The independent tranny cooler made a world of difference. Neither engine nor tranny gets over hot now.
FollowupID: 900776

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